I recently acquired this book. This evening, I solved two of the puzzles in chapter 9, but when I went to enter the solutions online, I found there was no code shown in the book. I then went through the rest of the book and there are no codes shown for any of the puzzles in chapters 10, 11 or 16, while there are codes shown in the warm up chapter.

Is this correct, or do I have a book that is missing some codes that should be there? If there are missing codes, what are they? I tried B4N1, but got a message saying there's no such puzzle.